Amazon.com: RV Water Heater Aluminum/Zinc Anode
Size and Material type: Aluminum/zinc anode rod, 4.5quotLong, 0.5diameter, 1/2quot Threads. Extends the life of a water heater by attracting corrosive elements in the water. If the anode rod is depleted and fully decayed, the water heater will begins to rust, then crack, fail and leak. Get rid of the embarrassing rotten egg smell : 4.4/5